feat: serializing output for solidity

[shreyas-londhe]

This PR adds nifty functions for serializing public outputs received from ZkVM proofs.

This is the output structure which can be decoded in the solidity smart contract.

    struct SolEmailVerifierOutput {
        bytes32 from_domain_hash;
        bytes32 public_key_hash;
        bool verified;
    }

    struct SolEmailWithRegexVerifierOutput {
        SolEmailVerifierOutput email;
        bool header_regex_verified;
        bool body_regex_verified;
        string[] header_regex_matches;
        string[] body_regex_matches;
    }